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# Technical informations about the IGATE system #
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Software:
The IGATE-system is based on 2 softwarepieces.

The nodesoftware "(X)NET 1.36 for Linux" is being used. Xnet hase been
developed by Jimy, DL1GJI. The software is closed source.

As a filteringmodul we use "flexigate". Flexigate is a development of Arsene,
LX1TB and has been enhanced by Thomas, DL9SAU. The enhancements will be
published through the open source code.

The linuxsystem is a Debian/stable with Kernel 2.4.

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Hardware (IGATE):
The IGATE-Server is a Siemens Server with Pentium III (Katmai) 500 MHz,
128 MB RAM and enough hdd storage.

It is build into a 19" rack at DB0FHN (University Nuernberg) with
Internetaccess through the german research and education network (DFN).

The primary IGATE will be replaced by an embedded system without fans and
movable parts and will be connected at the computer center of university
Nuernberg soon.

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The communication between the gateways ant the IGATE is passed through the
external softwre "flexigate". IGATE and "flexigate" use AXUDP at localhost.
"flexigate" and the gateways use also AXUDP, so "flexigate" will only pass
and change packages between the nodes.

Flexigate is listening on the default AXUDP-Port and on another port, because
some gateways can't use the "privileged" standardport. "flexigate" will
filter all destinations to the gateways (except IGATE itself) on the transfer
of the destinations.

So IGATE imports all destinations from the gateways, but exports only the
own Call IGATE.

"flexigate" can have partners with fix IP-address and fix UDP-sourceport.
It can also serve partners with dynamic IP-addresses and dynamic UDP-Source-
port. Spoofing-protection can be switched on by using dynamic DNS.

The backupsystem is still in development. IGATE-Backup should be switched on
automatically when IGATE fails.

Last change: 2005-02-02